Theoretical calculations will be made on hallucinogenic agents in the phenethylamine, amphetamine and tryptamine classes as well as others of more diverse chemical structure. These calculations will include molecular orbital and interaction energy predictions. Model systems will be studied for their ability to stimulate the interaction of moieties in the hallucinogens and possible receptor features. The ring portions of these molecules will be the principle focal point. We will attempt to expand on our previously developed SAR relationship to account for potency in a broader list of agents.